This right here: Linux From Scratch (LFS).
If your goal is to learn, there is no better way than retrieving each tool individually and compiling it from the bottom up. LFS is Gentoo ... without all the ease of use built in. More accurately, LFS is a just a set of instructions for where to go to get the code and how to compile everything you need to build a Linux system from the bottom up.
I don't live in the world of LFS or Gentoo, but my foray into LFS gave me a much greater appreciation for the distribution(s) I do use as daily drivers. I greatly appreciate my distribution maintainers.
Apologies for the late response. I hadn't posted any rules yet, but I'm certainly open to suggestions.
I'd like to lean in the direction of less than more on the rules and then deal with problems as they come up.
I'll modify the description to include some brief rules, and then we probably need to bring it up for discussion at some point. Provided we start to see some traffic.
[Full disclosure: I'm a director at a large software company (not ESRI!), and I'm not entirely sure our own HR department includes pay range in all their job postings -- although that may be changing right now with various rule changes at the state level in the US.]